During the 1800s, Lord Palmerston (nicknamed Lord Cupid because of his numerous love affairs) was one of the most powerful English politicians: a war secretary, foreign secretary, home secretary, and prime minister.

His famous Mayfair house, where he welcomed London’s rich and powerful, is located across from Green Park on Piccadilly. It’s readily identified because it’s the only Piccadilly property that’s set back from the street. The two gates and the curved driveway make it easy to recognize.

In 1850, the residence was known as Cambridge House because Queen Victoria’s uncle, the Duke of Cambridge, owned it. On 27 June, the queen visited him and attracted so much attention that by the time she emerged from the house, a considerable crowd blocked the street, preventing her carriage from leaving.

One member of the crowd, Robert Francis Pate, was more interested in walking onward than looking at the queen. Angry that his way was blocked, he pushed his way toward the royal carriage, raised his cane, and struck Queen Victoria across the forehead. Shockingly, he drew blood. (For the full scene, preorder Inspector of the Dead.) Pate was the fifth man to threaten the queen. Declared as insane as it’s possible for a sane person to be, he was exiled to Van Diemen’s Land (present day Tasmania).

After the Duke of Cambridge died, Lord Palmerston bought the property, which continued to be known as Cambridge House. Following Lord Palmerston’s death in 1865, it was acquired by the Naval and Military Club, which placed traffic-direction signs—IN at one gate and OUT at the other—causing the property to be nicknamed the In and Out Club. If you look closely at the initial photograph of Cambridge House, you can see the modern versions of the signs. Also, note how different the front wall looked in 1850 compared to now.

Deserted since the 1990s, Cambridge House fell into disrepair. Although two billionaire brothers announced their intention to renovate it for £214 million and make it the most expensive residential property in London, repairs had not begun as of early 2014, and the ghost of Lord Palmerston seemed to haunt it.

Beyond a fence on the opposite side of Piccadilly, this is the spectacular view of Green Park that Lord Palmerston would have enjoyed. The middle path leads down to Buckingham Palace. In Murder as a Fine Art, Thomas De Quincey flees for his life through this park.